Witchell was born in Shropshire. He was educated at Epsom College, a British public school in Surrey, and at Leeds University, where he read Law and edited the Leeds Student newspaper. In 1974 Terence Dalton Limited published Witchell's book The Loch Ness Story, a history of alleged sightings of the Loch Ness Monster. Witchell has worked for the BBC since 1976. Witchell, along with Sue Lawley, became the first newsreader of the BBC Six O'Clock News when the programme was launched on 3 September 1984. In 1988, the Six O'Clock News studio was invaded during a live broadcast by a group of women protesting against Britain's Section 28. Witchell grappled with the protesters and is said to have sat on one woman, provoking the ambiguous frontpage headline in the Daily Mirror, "Beeb man sits on lesbian". During the 1989 journalist strike, Witchell was one of the few newsreaders to turn up to work. He was branded a "scab" for this action. In 1989 he moved from the evening to the breakfast news slot, where he remained for five years. During the 1991 Gulf War he was a volunteer presenter on the BBC Radio 4 News FM service. He was the first reporter to relay the news of the 1979 death of Lord Mountbatten, the 1987 Zeebrugge ferry disaster, the 1988 Lockerbie disaster, and the 1997 death of Diana, Princess of Wales.
Royal correspondent
In 1998, Witchell became a royal and diplomatic correspondent. In 2002, his obituary of Princess Margaret, Countess of Snowdon, recorded some time before her death but screened immediately after the announcement of her death, was reportedly not well received at Buckingham Palace, as it mentioned her lovers and "copious" consumption of whisky. Witchell provoked royal displeasure again in 2005. At a press conference at the Swissski resort of Klosters, Witchell asked Charles, Prince of Wales, how he and his sons were feeling about his forthcoming marriage to Camilla Parker Bowles. After a response from his son Prince William, the Prince of Wales said under his breath, and referring to Witchell: "These bloody people. I can't bear that man. I mean, he's so awful, he really is." Witchell himself was then in the headlines. The BBC defended their reporter saying: "He is one of our finest. His question was perfectly reasonable under the circumstances".